Vibrating surgical instrument

ABSTRACT

A vibrating tissue separator suitable for use in separating a lenticule established by a femtosecond laser during a smile procedure may include a surgical implement such as a blunt spatula mounted on a handle that carries a haptic actuator for applying vibratory motion to the surgical implement. A damping arrangement may be provided to isolate the surgeons hand from the vibrations which would otherwise be transmitted through the handle. The actuator may apply a linear vibration along the axis of the handle which applies a lifting and chopping motion to the tip of a surgical implement having a bend. The tip may be suitable to the tissue being separated. For example, for SMILE lenticule separation, a blunt or semi-sharp spatula, blunted wire or loop may be used. The direction of vibration at the tip may be changed by rotating the implement in a plane other than the plane of the bend or by rotating an actuator such as an LRA with respect to the handle.

BACKGROUND OF THE INVENTION

The invention relates to a surgical instrument and more particularly avibrating tissue separator.

DESCRIPTION OF THE RELATED TECHNOLOGY

Refractive eye surgery is used to improve the refractive state of theeye and decrease or eliminate dependency on glasses or contact lenses.This can include various methods of surgical remodeling of the cornea(keratomileusis), lens implantation or lens replacement. Refractive eyesurgeries are used to treat common vision disorders such as myopia,hyperopia, presbyopia and astigmatism.

In 1930, a Japanese ophthalmologist, Tsutomu Sato, attempted to performrefractive surgery by making radial cuts in the cornea, correctingeffects by up to 6 diopters. The procedure produced a high rate ofcorneal degeneration, however, and was soon rejected by the medicalcommunity.

Jose Barraquer developed a refractive surgery technique in 1963 calledkeratomileusis, meaning corneal reshaping, enabled correction of myopiaand hyperopia. Keratomileusis involves removing a corneal layer,freezing it so that it could be manually sculpted into the requiredshape, and reimplanting the reshaped layer into the eye.

Another procedure, radial keratotomy (RK) involves making a number ofcuts in the cornea to change its shape and correct refractive errors.The incisions are made with a diamond knife. Following the introductionof RK, doctors routinely corrected nearsightedness, farsightedness, andastigmatism using various applications of incisions on the cornea.

In 1980, Rangaswamy Srinivasan, a scientist at IBM found that an excimercould be used to cut organic tissues with high accuracy withoutsignificant thermal damage. The discovery of an effective biologicalcutting laser, along with the development of computers to control it,enabled the development of new refractive surgery techniques.Photorefractive Keratectomy (PRK), or keratomileusis in situ (withoutseparation of corneal layer) was an early laser vision correctiontechnique to reshape the cornea. In PRK surface cells, called epithelialcells are removed and the curvature of the cornea is then modified byapplying a laser treatment to its surface. The corrected curvature ofthe cornea then allows light to come into focus accurately within theeye. Another photorefractive surgical technique called LASIK surgeryinvolves cutting a flap in the cornea and pulling it back to expose thecorneal bed, then using an excimer laser to ablate the exposed surfaceto the desired shape, and then replacing the flap.

LASIK and PRK were broad-beam techniques. Several enhancements haveimproved certain aspects of refractive surgery. U.S. Pat. No. 5,520,679,the disclosure of which is expressly incorporated by reference herein,disclosed a scanning laser (or flying spot laser) thought to be saferand able to be constructed at a lower cost, more compact, and performmore precisely and with greater flexibility than prior laser systemsusing the theory of beam overlap and of ablation rate and coagulationpatterns for system parameters. According to U.S. Pat. No. 5,520,679,scanning lasers are selected with energy of 0.01-10 mJ, repetition rateof 1-10,000 pulses/second, pulse duration of 0.01 nanoseconds to a fewhundreds of microseconds, and with spot size of 0.05-2 mm for use withrefractive laser surgery. The scanning laser system patent describedvarious lasers which have been used for refractive surgeries and thatthe then existing ophthalmic lasers had a “high-power requirement in UVlasers for photorefractive keratectomy; large size and weight; highmaintenance cost and gas cost (for excimer laser), and high fiber-costfor contact-type laser coagulation.”

Another enhancement for refractive surgery is the use of an eye-trackingdevice to prevent decentration in LASIK procedures. The idea is tocompensate for eye-movements made during a laser refractive eye surgerysuch LASIK.

In a LASIK procedure Excimer laser ablation is done under apartial-thickness lamellar corneal flap. The surgeon uses either amicrokeratome or a femtosecond laser to cut a flap of the cornealtissue. The flap is lifted like a hinged door. A microkeratome is aprecision surgical instrument with an oscillating blade designed forcreating the corneal flap.

Femtosecond lasers have numerous advantages over mechanicalmicrokeratome based procedure. Microkeratome related flap complicationslike incomplete flaps, buttonholes or epithelial erosion are eliminatedwith femtosecond laser procedure. Absence of microscopic metal fragmentsfrom the blade will reduce the risk of lamellar keratitis also. When afemtosecond laser flap is created in LASIK (the same femtosecond laseras used in the SMILE procedure used) with the same settings, the LASIKflap easily separates, even with a very blunt instrument such as a25-gauge cannula.

Another refractive procedure is SMall Incision Lenticule Extraction(SMILE), originally called Femtosecond lenticule extraction (FLEx), is aform of laser based refractive eye surgery developed by Carl ZeissMeditec used to correct myopia, and astigmatism. Although similar toLASIK laser surgery, the intrastromal procedure shown in the SMILE isnovel in that it uses a single femtosecond laser referenced to thecorneal surface to cleave a thin lenticule from the corneal stroma formanual extraction. It has been described as a painless procedure. Forcandidates to qualify for this treatment, they have their corneal stromathickness checked to make sure that post-operative thickness won't betoo thin.

The lenticule to be extracted is accurately cut to the correctionprescription required by the patient using a photo disruptionlaser-tissue interaction. The method of extraction can be via aLASIK-type flap, but more recently a flapless technique makes a smalltunnel incision in the corneal periphery.

The femtosecond laser does not completely separate the lenticule, ablunt spatula or a specially designed instrument is inserted through theincision to separate and remove the lenticule through the incision. Caremust be taken to ensure that the lenticule is completely detached priorto removal by forceps. The procedure is minimally invasive compared withflap based treatments and collateral damage to surrounding tissue isminimized due to the high speed of the femtosecond laser.

A surgeon performing femtosecond laser created lenticule removal mustdevelop the skill to remove the lenticule without causing trauma ordamage to the stromal tissue.

Sinha, Ranesh, et al., Ophthalmic Surgical Instruments, Jaypee BrothersMedical Publishers Ltd., 2017, is expressly incorporated by referenceherein and shows various instruments which are used in ophthalmicsurgery.

SUMMARY OF THE INVENTION

An object is to provide a surgical instrument that may be used toseparate tissue without damage to surrounding tissues.

It is a further object to provide a vibrating instrument for separatinglayers, particularly along lines or planes of weakness, such aninstrument may be useful for delicate operations where use of manuallyinduced forces alone risks damage to surrounding tissue or materials.Application of vibratory forces may be useful in separating a tooth andsurrounding gum tissue. Such an instrument may be helpful in cataractand other ocular surgery procedures such as to open primary andsecondary femtosecond laser created corneal incisions in femtosecondlaser assisted cataract surgery and in other procedures to raise a flapin femtosecond LASIK and release adhesions under the flap; to aid in theproper placement of an Implantable Collamer Lens (ICL); and an Intactscorneal separator.

It is a further object to provide an instrument that has a vibratingfrequency far below ultrasonic frequencies. Vibration frequencies areset to exceed manually applicable frequencies but not so high as tocreate a risk of damage. For example, it is an object to provide adevice for use in ocular surgery that is not designed to modifyrefractive error or refractive properties of corneal tissue, inparticular, to be more effective and safer than manual separation butnot intended to have a different resulting structure than manualseparation.

It is a further object to provide a vibrating instrument to assist inseparating a lenticule formed by application of a femtosecond laser orby a photodisruption laser-tissue interaction.

According to an advantageous feature a vibrating tissue separator mayinclude a handle sized as a handheld surgical instrument. An actuatormay be mounted in the handle and a surgical implement may bemechanically linked to the handle. A control circuit may be connected tothe actuator and a power source may be connected to the control circuit.The surgical implement and the actuator may be fixed to the handle, orthe surgical implement may be slideably mounted in a channel in thehandle.

A seal may be present in the channel between the implement and thehandle. A damping element between the handle and the actuator may beprovided and the actuator may be slideably mounted in a channel in thehandle. The actuator may be an LRA. The damping element may be a spring,a shock absorber, or a block of elastomer.

The control circuit may be a switch. The control circuit may include afeedback controller configured to increase power output in proportion toresistance in movement of the actuator. The control circuit may be ahaptic driver having closed loop frequency control.

The directional components of the vibratory movement may be adjustedusing a vibrational translator. The vibrational translator may be ahinge in the surgical implement located between a proximal portion ofthe surgical implement and a distal portion of the surgical implementwhere the distal portion of the surgical implement exhibits a bend. Thehinge may be a bell crank. Another implementation of the vibrationaltranslator may be by having the actuator connected to a pivot mount,where pivoting the mount will change the direction of linear vibrationof an LRA. The pivot mount may be a bell crank or, may be a pivot to setthe angle of radial vibration around a pivot axis extending along thelength of a handle.

The surgical implement may have a tip in the form of a semi-sharpspatula, a blunt spatula, a round blunted wire, a loop, or other shapeaccording to preference of a surgeon.

It is an object to provide a vibrating surgical tool, such as avibrating blunt spatula which may be used for to separate tissue. Thecornea is a flexible, relatively inelastic, clear structure made of fivelayers. The layer that is treated with refractive surgery is the stromallayer which has an orientation of many fine horizontal lamellae.Historically, lamellar corneal transplants were performed by using asemi-sharp spatula to separate these layers manually. In the SMILEprocedure, the desired layers are partially pre-cut with the femtosecondlaser allowing a similar handheld instrument to complete the tissuedissection.

While SMILE has many properties making it more desirable to a patientthan other refractive procedures, such as less tissue being cut and asingle laser used which is not subject to some of the variables whichcan result in excimer laser variability, SMILE is technically moredifficult to perform.

In a SMILE procedure, a femtosecond laser makes many spots closetogether, but not touching in a spiral pattern. First the deeper layeris cut with a curvature to match the desired refractive error change insphere and cylinder. Internal side cuts may then be made by thefemtosecond laser which establishes a 30 micron edge to a lenticule.Then an upper layer is cut which is parallel to the corneal surface,very similar to a flap. A small opening is created to allow a bluntspatula or other instrument to be introduced to complete the tissuedissection first of the upper and then the lower layer, after which thetissue may be removed with a forceps. The resulting tissue, orlenticule, is very thin. Typically, the resulting lenticule isapproximately 30 microns on the edge and varying to between 30 and 120microns thick in the center, with a diameter of approximately 6.0-7.0mm.

The laser used in SMILE does not fully cut the tissue for severalreasons. One is that the spots, even if touching are round and therewill still be an uncut region between spots since they cannot overlap.The second is that there would be a very long time to complete theprocedure, which has risks of the patient moving among others. The thirdis that the amount of energy delivered to the eye would be much higherand have potential risks related to heat and other effects. In practice,the spots are 1 micron in diameter and usually spaced 4.5 microns apart.The femtosecond laser works by creating very short duration high pulseenergy spots that result in a plasma and a surrounding shock wave. It isthis shock wave that cuts or weakens the surrounding tissue. This effectis variable from patient to patient and to some extent from laser tolaser. Therefore, the perforations created by the laser spots are notconsistent across patients and thus, the difficulty of separating thelenticule is not consistent between patients.

The disclosed vibrating surgical tissue separator solves the problem ofseparating the lenticule. As is known, movement of a blade increases itseffective sharpness or cutting action. This is one possible modalitythat can be accomplished by a vibration assistance to the semi-sharpspatula. There are two other modes of effect possible: i) apushing/chopping motion and ii) a lifting motion. The vibratinginstrument may apply a combination of the three modes, set by a surgeon,to assist in separating structures, such as a lenticule created in aSMILE procedure.

It is an advantageous feature to provide an instrument which may apply avibration imparting a motion having a significant lifting component. Ithas not been reported that a lifting motion may enhance the ease oflenticule separation. A conventional spatula cannot apply an effectivelifting motion due to the structure of the cornea and spatialimitations. In traditional femtolasik, once the perimeter of the flaphas been cut, insertion of a cannula or blunt spatula in the pre-cuttissue plane a primarily lifting with slight pushing motion easilyseparates the flap. In SMILE, there is no peripheral circumferentialcut, and the only entrance to the surgical area is through a small 30 to45 degree opening. Therefore, while it is possible to both push and movefrom side to side the conventional spatula, in the enclosed space, it isnot possible to provide any lifting force. The cornea has a high young'smodulus, it does not stretch very much so after just a small amount oflifting, in an enclosed restricted space, the lifting is limited. Withvibration in a lifting direction at a relatively high frequency, theseparation by lifting is enabled.

In the design of this device, by changing the angle of the spatula fromwhere its attachment exits the device to the tip, a varying combinationof pushing (the motion if the wire is straight to the spatula) tolifting (if the wire is bent 90 degrees towards the end) isaccomplished. The relative amounts of lifting and chopping depends onthe angle of the surgical implement. The lifting with vibration is verysmall amplitude of a fraction of a millimeter but at a relatively highfrequency of hundreds of times per second, which cannot be accomplishedmanually. Thus the pushing and lifting are automated, and the surgeoncan swing the cannula side to side to accomplish some cutting motion aswell. The cutting motion is the most dangerous to continuing theseparation beyond the desired pre-cut location, and therefore automationshould be minimized in the design.

An ERM motor which vibrates by an eccentric rotating motor shaft whichvibrates at approximately 8000 Hz or higher may be used, but thisconfiguration appears to be at a higher frequency than needed.Furthermore, it is implemented with a DC motor with a DC source and,thus may be difficult to control due to it being controlled only byvarying the voltage applied, which limits control of the amplitude andfrequency as well as direction of the vibrations.

Advantageously an LRA motor that runs on AC voltage, and has a frequencythe same as the AC sine or square wave fed to them may be used. Usingeither a signal generator, such as an H-Bridge, or a microprocessor orother integrated circuit specialized for delivering AC pulses from a DCsource allows for control of frequency, pulse pattern, and otherdesirable pulse characteristics. The frequency for these LRA devices asutilized in prototypes is in the range of 200-300 Hz which seemsadequate for the intended purposes. An LRA has vibration primarily alongone axis (Z axis) which can be aligned in the desired direction ofmovement, and there are microprocessors allowing for smart control ofLRA's which are helpful. For example, a Dialog Semiconductor DA7282LRA/ERM Ultra-Low Power Haptic Driver with Multiple Input triggers andIntegrated Waveform Memory, shown in Dialog Semiconductor DA7282Datasheet Revision 3.0 30 Jul. 2019 CFR0011-120-00, expresslyincorporated by reference herein, may be used to drive the LRA andimpart a cyclic vibration of increasing and decreasing amplitude overtime, can be tuned to the exact resonance of the device, and can bemodulated based on the resistance to vibration with increasing thecurrent and or voltage to maintain a given frequency. The resistance tovibration may be determined by sensing the phase between current throughand voltage applied to the LRA. In addition, the frequency as well asthe amplitude of the vibration may be controlled by changing primarilythe sine wave frequency delivered and/or the voltage delivered to thedevice.

There is also the possibility of using two LRA devices in series toincrease or modulate the effect between them. When run in phase theamount of vibration is the sum of each individually, and when out ofphase they can cancel out the effect. LRA's also have the advantage ofextremely low latency and provide therefore the desired effect withoutany delay from the input programming.

The driver may compensate for the difficulty that a surgeon mayencounter manually adjusting the operation of the LRA while conductingdelicate eye surgery. The driver may automatically vary the intensity ofvibration. The device can auto adjust the impedance to correct forvarying amounts of resistance during the procedure, thus making it a“smart device” where the surgeon advances the tip and the amount ofvibration will vary from a baseline level depending on the amount ofresistance encountered. There is also the capability to give tactilefeedback to the surgeon with a series of short haptic sensations. Thesecan be used to indicate activation of the device or changing conditionsand after it is removed from the eye that it has been turned off.

A device may be approximately 100 mm long, not including the tip, whichwill be designed to resemble the conventional tip on a manual all metalsurgical instrument and be approximately 8.5 mm in widest diameter withtapering at either end. This will be approximately the size that asurgeon is familiar with for such a standard surgical instrument. Theremay be an on/off switch or a film that can be pulled for activation withhaptic feedback of operational self-check and ready status. The devicemay be single packaged as sterile and disposable. One device can be usedfor both eyes and then discarded. The body/handle may be made of plasticwith internal batteries, controller chips, LRA motor, spring, andinsulation from vibration with a small, sealed hole in the front fromwhich the treatment wire protrudes and then bends to the functionalspatula tip.

A hinge, such as a Bell Crank hinge may be used in the instrument totranslate movement in one direction to another. The angle of thesurgical implement may be adjusted at the hinge. A non-hinge option toadjust motion direction is to change the orientation of the LRA motor toaccommodate the desired motion or alternatively use an ERM motor whichvibrates in multiple directions.

While the vibrating tissue separator is suited for eye surgery, asimilar type of situation occurs in other fields such as dentistry,orthopedic surgery, neuro-surgery, or any field where tissue must beseparated from another tissue plane from within a restricted space andthus similar tools to this one would have applicability in these othermedical disciplines.

The surgical implements used in the vibrating instruments may includeblunt spatula, semi-sharp spatula, and other implements that will haveenhanced performance when vibrations are imparted to such implement,including separators, hooks, wires, loops, and those shown in Sinha,Ranesh, et al., Ophthalmic Surgical Instruments, Jaypee Brothers MedicalPublishers Ltd., 2017.

Various objects, features, aspects, and advantages of the presentinvention will become more apparent from the following detaileddescription of preferred embodiments of the invention, along with theaccompanying drawings in which like numerals represent like components.

Moreover, the above objects and advantages of the invention areillustrative, and not exhaustive, of those that can be achieved by theinvention. Thus, these and other objects and advantages of the inventionwill be apparent from the description herein, both as embodied hereinand as modified in view of any variations which will be apparent tothose skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic diagram of a surgical instrument.

FIG. 2 shows vibrating surgical instrument with a fixed actuator andfixed surgical implement.

FIG. 3 shows an embodiment with of the vibrating tissue separator with areduced translation of vibratory forces to the handle.

FIG. 4 shows an embodiment of the tissue separator which includesfurther damping structures for reducing translation of vibrationalforces to the handle.

FIG. 4A, shows an alternative implementation of the instrumentillustrated in FIG. 4 .

FIG. 4B, shows a further alternative implementation of the instrumentillustrated in FIG. 4 .

FIG. 5 shows a schematic of an actuator control circuit.

FIG. 6 shows a side view of a vibrational translator for use in avibrating tissue separator.

FIG. 7 shows a top view of a vibrational translator for use in avibrating tissue separator.

FIG. 8 shows an alternative implementation with a radially vibratingLRA.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Before the present invention is described in further detail, it is to beunderstood that the invention is not limited to the particularembodiments described, as such may, of course, vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular embodiments only, and is not intended to belimiting, since the scope of the present invention will be limited onlyby the appended claims.

Where a range of values is provided, it is understood that eachintervening value between the upper and lower limit of that range isencompassed within the disclosed subject matter.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, a limitednumber of the exemplary methods and materials are described herein.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

FIG. 1 shows a schematic diagram of a surgical instrument, in particulara tissue separator. The instrument may rely on a blunt tip or bladeuseful to separate tissue, such as along a plane created by afemtosecond laser. For example, a corneal incision, flap or a lenticulecreated by a laser in a SMILE procedure. The instrument may also beuseful to separate material along any line, plane, or area of weakness.The blunt tip may be a spatula to avoid using a sharp instrument whichcould damage surrounding tissue, particularly if misapplied. The use ofa blunt instrument can reduce the incidence of accidentally cuttingtissue which should remain intact. The use of a blunt instrument, suchas a spatula, however, has been found to be difficult to manipulate anddifficult to use to separate tissues such as a lenticule as createdduring a SMILE refractive technique. The femtosecond laser systemachieves the best results when the laser is not set to completelyseparate the lenticule from the remaining corneal tissue. The treatmentparameters of the laser are typically set to achieve enhanced visualresults and not for ease of separation of the lenticule. It has beenfound that placing very closely spaced spots with the laser which wouldease separation of a lenticule may delay visual recovery and does notgive the best visual outcome. To avoid the effects of many closelyspaced laser spots, a surgeon must complete the dissection of the planecreated with the laser and separate and extract the lenticule. Theinstrument may include a spatula which vibrates preferably, at afrequency below ultrasonic frequencies. The frequency range found to beeffective is between 200-500 Hz, but all frequencies in the audiblerange can be reproduced with LRA devices and therefore frequenciesbetween 20-20,000 Hz may be acceptable. The instrument may be a poweredvibratory spatula which may include a power supply 11, for example, abattery connected through a control mechanism 12 to an actuator 13mounted within a handle 14.

The instrument may be provided with a surgical implement or head 15 asthe tissue separating implement. The power source 11 may be matched tothe actuator 13. For example, if the actuator requires a DC voltage, thepower supply 11 will put out a DC voltage level. Alternatively, and inthe preferred embodiment, if the actuator requires an AC voltage, thepower source 11 may be arranged to provide an AC voltage. A controlcircuit 12 may be provided to allow a surgeon to apply power to theactuator 13 and disconnect power from the actuator 13. The controlcircuit 12 may be a switch or may be more involved in order to regulatevoltage levels provided to the actuator 13. The head 15 having asurgical implement, such as a blunt spatula, may be arranged to vibrateby application of vibratory energy generated by the actuator 13.

An actuator is a device that produces motion by converting energy andsignals going into the system. The motion it produces may be eitherrotary or linear. Linear actuators, as the name implies, produce linearmotion, and can move forward or backward on a set linear plane. Linearactuators typically travel a set distance in either direction. Rotaryactuators on the other hand produce rotary motion. Haptic actuators areavailable which are suitable to the vibratory instrument. A linearresonant actuator (LRA) and an eccentric rotating mass (ERM) motor arecommon haptic actuators which may be used in the surgical instrument.Haptic actuators and haptic drivers are well known and widely available,albeit not for the current application. See, for example, TexasInstruments, SLOU 389A—May 2014—Revised June 2014, User's Guide,DRV2605L ERM and LRA Haptic Driver Evaluation Kit, retrieved Oct. 14,2021, and Dialog Semiconductor, DA7282, LRA/ERM, Ultra-Low MultipleInput Triggers and Integrated Waveforth Memory, CFR 00011-120-0,Datasheet Revision 3.0, 30 Jul. 2019, the disclosures of both are herebyexpressly incorporated by reference herein. The driver may be controlledby a microcontroller, for example, a PIC18F06/16Q41, 14/20 Pin,Low-Power, High Performance Microcontroller with XLP Technology,available from Microchip Technology Inc. and described in DatasheetDS4002214E, the disclosure of which is expressly incorporated byreference herein. There are many other commercially availablemicrocontrollers suitable to this application.

FIG. 2 shows a vibrating surgical instrument with a fixed actuator 23and fixed surgical implement 25. The instrument shown in FIG. 2 includesa power supply 21 connected through a control such as a switch 22 and anactuator 23 or other activation mechanism. The control is illustrated asa switch. However, it should be recognized that the control may includea microcontroller and a haptic driver of the type discussed above. Theswitch may include a button which extends through the surface of ahandle 24. When a surgeon depresses or slides the switch 22 power issupplied to the actuator 23 causing a vibration in the instrument handle24. The vibration is translated to a head 25 fixed to the handle 24. Theembodiment shown in FIG. 2 has the advantage of simplicity in design andconstruction, however, a user may find that the amount of vibrationtranslated through the handle 24 reduces tactile sensation needed formicrosurgery. This is more expected in the ERM type vibrators. In theLRA vibrators, it is easier to isolate the vibration to only the tip 25with less transmission through the handle 24. It may also be awkward tomanually activate the device repeatedly. Therefore, smart control wherethe device is activated at a low level but can increase the vibrationdue to impedance may be preferred. As a matter of preference,translation of the vibration however may provide a direct indication ofthe operation of the actuator to the user. The switch may remain on whenreleased or be a switch that requires contact to remain on.

FIG. 3 shows an embodiment of a vibrating tissue separator with areduced translation of vibratory forces to the handle 34. The instrumentshown in FIG. 3 includes a power supply 31 connected through a controlsuch as a switch 32 and an actuator 33. The switch 32 may include abutton which extends through the surface of a handle 34. When a surgeondepresses or slides the switch 32, power is supplied to the actuator 33causing a vibration in the instrument handle. The vibration istranslated to a head 35. As shown in FIG. 3 , the actuator may bemounted within a channel 37 of the handle so that motion is imparted tothe surgical implement 35 which extends through the channel 37.According to the embodiment of FIG. 3 , the surgical implement 35 is notrigidly linked to the handle 34. For example, the surgical implement 35extending through the channel 37 maybe smaller than the channel. A seal36 may be provided between the surgical implement 35 and the handle 34to prevent penetration of liquids and other contaminants into thesurgical instrument. The seal will facilitate sterilization of theinstrument. The seal 36 may be silicone or other appropriate materialwhich will withstand an autoclave sterilization process without losingits integrity or flexibility. In addition, the seal 36 may provide adamping effect to the head 35.

FIG. 4 shows an embodiment of the tissue separator which includesfurther damping structures for reducing translation of vibrationalforces to the handle 44. The instrument shown in FIG. 4 includes a powersupply 41 connected through a control such as a switch 42 and anactuator 43. The switch may include a button which extends through thesurface of a handle 44. When a surgeon depresses or slides the switch42, power is supplied to the actuator 43 causing a vibration in theinstrument handle. The vibration is translated to a head 45. As shown inFIG. 4 , the actuator may be mounted within a channel 47 of the handle44 so that motion is imparted to the surgical implement 45 which extendsout of the channel 47. According to the embodiment of FIG. 4 , thesurgical implement 45 is not rigidly linked to the handle 44. Forexample, the surgical implement 45 extending through the channel 47 maybe smaller than the opening of the channel 47 at the end of the handle44. The opening of the 44 and the portion of the surgical implement 45extending through the opening of the channel 44 may respectively besized to allow the surgical implement 45 to slide in the channel 47. Aseal 46 may be provided between the surgical implement 45 and the handle44 at the opening of the channel 47 to prevent penetration of liquidsand other contaminants into the surgical instrument. The seal willfacilitate sterilization of the instrument. The seal may be silicone orother appropriate material which will withstand an autoclavesterilization process without losing its integrity or flexibility. Theembodiment according to FIG. 4 has an actuator 43 that is not rigidlyattached to the handle 44. A vibrational damping element 48 is shownschematically as a spring, may be added to the surgical instrument. Thedamping element 48 is provided to further isolate the actuator 43 fromthe handle 44. Other elastomeric structures may be provided to isolatethe handle 44 from a linking element 49 and other intermediate elementsto the surgical implement 45. One end of the damping element 48 may befixed relative to the handle 44 while the other end is fixed to alinking element 49 (and relative to the surgical implement 45). In thisconfiguration, the linking element 49 is mechanically isolated from thehandle structure 44. For example, a spring may be mounted in a cylinderinstalled in a channel 47 of the handle 44. One end of the spring may befixed to the base of the channel (part of the handle) and the other endof the spring may be fixed to a linking element 49 such as a piston. Thelinking element 49 may extend through the channel 47 and connected to abattery 41 which is connected to a mechanical switch 42 and then to anactuator 43. The battery 41, mechanical switch 42, an actuator 43 may beall contained in the channel of the handle, but not rigidly fixed to thehandle structure itself. The surgical implement 45 may be connected tothe actuator 43 but not fixed to the handle 44.

FIG. 4 a , shows an alternative implementation of the instrumentillustrated in FIG. 4 , but with the switch 42 a and battery 41 a beingmounted in the handle 44 a along with one end of the damping element 48a. The linking element 49 a and actuator 43 a are not rigidly fixed tothe handle and may move within the channel 47 a.

FIG. 4 b , shows a further alternative implementation of the instrumentillustrated in FIG. 4 , but with the battery 41 b being rigidly mountedin the handle 44 b along with one end of the damping element 48 b. Thelinking element 49 b and actuator 43 b are not rigidly fixed to thehandle and may slide or move within the channel 47 b. The switch 42 b isshown only schematically as the mechanical and electrical structure arenot intended as limitations switch 42 b may represent control andactivation circuitry as described hereafter.

FIG. 5 shows a schematic of an actuator control circuit. The controlcircuit according to FIG. 5 allows resistance encountered by thesurgical implement to control the magnitude of the operation of theactuator. The control circuit according to FIG. 5 is designed so that,optionally, to a limit, the forces created by the surgical implementwill increase the magnitude and/or frequency of vibration. Theresistance based variable control permits an operation of the instrumentwhere a low level of vibration is generally utilized for tissueseparation, however, if resistance to the forces applied to the surgicalimplement increase, the magnitude of vibration excursion can beincreased to compensate for the resistance encountered. An increase in“resistance” may be sensed by detection of a reduction in the frequencyof the vibration. The feedback circuit may then increase the current andor voltage to maintain the desired frequency of vibration. FIG. 5 showsa power supply 51 connected through an actuating switch 52. The driver58 may be provided to apply a control voltage level to the actuator 53.The voltage control may be applied through a feedback channel. A sensor60 is provided to detect vibration of the implement. For example, whenresistance is encountered, the level of vibration may be decreasedthrough the encountered resistance. A sensor 60 may be provided todetect changes in the operation parameters of the surgical instrument55. The sensors may be conditioned through certain limits. For example,the limits may provide for a base vibration level when no force isapplied to the surgical implement. The sensor may be arranged to detectthe level of motion imparted to the surgical implement. As theresistance increases, the motion will decrease. This decrease motion maybe detected by sensor 60 to a variable control in the driver feedbackloop 59. When resistance increases, motion will decrease andamplification will increase. The limit 61 may be provided to controladjustments of the variable control 59 so as to contain the vibrationlevel. In addition, the vibration level may be limited to a set amountno matter how much force. In addition, the limit may operate to providea minimal vibratory force when the instrument is actuated.

In an actual implementation the control circuit of FIG. 5 , may beimplemented using a micro-controller, such as the Microchip PIC18F06 anda Haptic Driver chip such as the Dialog Semiconductor DA7282. Theresistance encountered by the implement may be sensed and the actuatormay be controlled using internal feedback and monitoring by the hapticdriver chip or by the microcontroller monitoring the status informationmade available by the Haptic Driver. As described in the DA7282Datasheet, the DA7282 is a haptic driver that features frequency controlwithin an onboard Waveform Memory and three distinct GPI inputs, fortriggering up to six distinct sequences. The device controls the levelof drive across the load and senses the movement of the actuator. Thedriven waveform is generated by a current regulated loop using ahigh-frequency PWM modulation. The differential output drive features aswitching regulator architecture with H-bridge differential drive acrossthe load. The drive level is based on the sequence from the data sourceselected by I2C interface, input PWM signal, or Waveform Memory. DA7282is capable of closed-loop actuator monitoring while driving to enablecalibration-free playback, frequency tracking (LRA only), ActiveAcceleration, Rapid Stop, and actuator diagnostics. Continuous resonantfrequency tracking can be enabled while driving an LRA to track themechanical resonance of the actuator through closed-loop control.

FIGS. 6 and 7 show a vibrational translator 61 for use in a surgicalinstrument such as a vibrating tissue separator. FIG. 6 shows a sideview of the vibrational translator 62. FIG. 7 shows a side view of thevibrational translator 62. The vibrational translator 62 may be usedwith any of the foregoing embodiments in order to adjust the directionof movement of the surgical implement 25, 35, 45, 45 a, and 45 b and maybe placed in the intermediate portion of the proximal segment of thesurgical implement. Depending on the particular application, a surgeonmay wish the instrument to impart a lifting motion, i.e. perpendicularto a flattened face of the surgical implement, a slicing motion, i.e.parallel to a line defined by leading edge of the surgical implement, ora pushing motion, i.e. perpendicular to a line defined by the leadingedge of the surgical edge or any combination thereof. The translation ofthe motion may be established using a vibrational translator. Oneimplementation is in the form of a hinge which allows rotation of anangled distal end 63 of a surgical implement relative to an implementarm 64 at the proximal end of the surgical implement extending from ahandle (not shown) where the implement arm may be connected to avibrating mechanism, for example as shown in FIGS. 2, 3, 4, 4 a, and 4b. Rotation of the hinge, such as a bell crank between the distal end 63and the proximal end 64 of the surgical implement has the effect ofchanging the direction of vibration at the distal end. The proximal end64 of the implement arm may carry a releasable locking mechanism 65 suchas a spring loaded bearing or other resilient protrusion. The angledsurgical implement, distal arm 63 may be connected to the proximal end64 of the implement arm by a pivot hinge 66. The distal end 63 (angled)of the surgical implement may have indents 67 distributed around aperimeter of the end of the angled surgical implement 62 that is pivotmounted to implement arm 63. The indents 67 are sized and positioned tocooperate with the releasable locking mechanism 65. In this way, thesurgeon may set the rotational position of the distal end 63 of theangled surgical implement to translate the vibrational direction of theimplement to set the relative amounts of a lifting, chopping and slicingcomponent of its vibration.

Alternatively the orientation of the LRA device could be modified tochange the orientation of the “Z” axis of the LRA resulting in a changein the direction of vibration at the distal end of the surgicalimplement. This may be accomplished by rotating an actuator mounted onor attached to a bell crank so as to provide oscillation about the pivotof the crank. Adjusting the orientation of the crank changes thedirection of vibration, and thus motion of the implement, to alter therelative components of slicing, chopping and lifting motions.

The electrical connections (not shown) for the embodiments shown inFIGS. 2, 3, 4, 4 a, 4, b and 6 are provided so as to accommodatevibrations induced by the actuator and relative movement of themechanical elements. The electrical connections may include slidecontacts which maintain continuity even in the event of relative motion.The controllers (not shown in FIGS. 2, 3, 4, 4 a, 4, b and 6) mayinclude a switch or other surgeon activated control, a driver, such as aDialog Semiconductor DA7282 Haptic Driver and a power supply controller.

FIG. 8 shows a further alternative implementation of a vibratingsurgical instrument. A surgical implement 81 is arranged at the distalend of implement arm 82. Implement arm 82 extends from the instrumenthandle 83. The instrument handle 83 has a central axis 84. End cap 85 isrotationally attached to the handle 83 and is provided to twist aroundthe axis 84 of the handle 83. A haptic driver, microcontroller, switch,and power source may be arranged in a recess not shown in the twistingend cap 85. An actuator arm 86 may extend from the end cap 85 throughthe hollow center of the handle 83. The distal end 87 of the actuatorarm 86 is configured to hold LRA 88. LRA 88 when activated vibrates inthe directions shown by arrows 89. The distal tip 90 of the actuator armis configured to engage implement arm 82 in order to move the implementarm 82 in the direction of vibrations 89, but is not fixed to implementarm 82 so that the actuator arm 86 may be rotated without rotating theimplement arm 82. Implement arm 82 may be connected to the handle 83 byan elastomeric resilient seal 91 at the distal end of the handle. Inaddition, the implement arm 82 may extend through a collar 92 whichoperates to relieve vibrational stresses on the seal 91 and which actsas a pivot point allowing seal 91 to act as a damping mechanism due toits elastomeric qualities. The conductor supplying electrical power maybe arranged through or on the actuator arm 86. The end cap 85 may berotated about the axis 84 to change the radial direction of vibration89. The implement arm 82 is rotationally fixed to the handle 83. Therotational alignment of the end cap 84 and the actuator 89 when set tobe perpendicular to the face of the surgical implement tip 81 willimpart a combination of pushing movement and lifting movement to theimplement tip 81. By rotating the end cap 85 90° the radial direction ofvibration of the LRA 88 is also changed by 90° degrees. Changing thedirection of vibration in this fashion will eliminate the lifting andpushing motion of the implement tip 81 and instead impart a slicingmotion.

The simplified version of the tissue separator shown in FIG. 8 may beprovided, which does not permit changing the vibration direction of theimplement head. In the simplified embodiment, the collar 92 may bereplaced by a pivot point and the end cap 85 may be rigidly connected tothe handle body 88 thereby eliminating rotation of the end cap 85,rotation of the actuator arm 86, and fixing the direction of vibrationof the LRA 88.

The techniques, processes and apparatus described may be utilized tocontrol operation of any device and conserve use of resources based onconditions detected or applicable to the device.

The invention is described in detail with respect to preferredembodiments, and it will now be apparent from the foregoing to thoseskilled in the art that changes and modifications may be made withoutdeparting from the invention in its broader aspects, and the invention,therefore, as defined in the claims, is intended to cover all suchchanges and modifications that fall within the true spirit of theinvention.

Thus, specific apparatus for and methods of use have been disclosed. Itshould be apparent, however, to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the spirit of thedisclosure. Moreover, in interpreting the disclosure, all terms shouldbe interpreted in the broadest possible manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

The invention claimed is:
 1. A surgical hand instrument for separatingtissue layers comprising: a handle sized as a handheld surgicalinstrument for freehand use; a vibrating actuator mounted in saidhandle; a surgical implement linked to said vibrating actuator, saidsurgical implement exhibiting a tip suitable for separating tissuelayers, wherein said surgical implement has a generally planar tip; acontrol circuit connected to said actuator; wherein said vibratingactuator is linked to said surgical implement to impart vibration tosaid tip and wherein said vibration includes a lifting component,wherein said lifting component is perpendicular to a plane defined bysaid generally planar tip and wherein said lifting component of saidvibration has a frequency of 200 Hz to 500 Hz; and a power sourceconnected to said control circuit.
 2. The surgical hand instrument forseparating tissue layers according to claim 1 wherein said surgicalimplement is fixed to said handle and said actuator is fixed to saidhandle.
 3. The surgical hand instrument for separating tissue layersaccording to claim 1 wherein said surgical implement is slidably mountedin a channel in said handle.
 4. The surgical hand instrument forseparating tissue layers according to claim 3 further comprising a sealin said channel between said surgical implement and said handle.
 5. Thesurgical hand instrument for separating tissue layers according to claim3 further comprising a damping element between said handle and saidactuator and wherein said actuator is slideably mounted in said channelin said handle.
 6. The surgical hand instrument for separating tissuelayers according to claim 5 wherein said actuator is a linear resonantactuator (LRA).
 7. The surgical hand instrument for separating tissuelayers according to claim 5 wherein said damping element is a spring, ashock absorber, or a block of elastomer.
 8. The surgical hand instrumentfor separating tissue layers according to claim 7 wherein said controlcircuit comprises a switch.
 9. The surgical hand instrument forseparating tissue layers according to claim 8 wherein said controlcircuit further comprises a feedback controller configured to increasepower output in proportion to resistance in movement of said actuator.10. The surgical hand instrument for separating tissue layers accordingto claim 9 wherein said control circuit further comprises a hapticdriver having closed loop frequency control.
 11. The surgical handinstrument for separating tissue layers according to claim 5 furthercomprising a second damping element arranged to interact with saidsurgical implement and provide a damping effect to said surgicalimplement.
 12. The surgical hand instrument for separating tissue layersaccording to claim 3 further comprising a vibrational translator,wherein said vibrational translator is a bend in said surgical implementlocated between said generally planar tip and a proximal portion of saidsurgical implement.
 13. The surgical hand instrument for separatingtissue layers according to claim 12 wherein said bend in said surgicalimplement is provided by a hinge in said surgical implement locatedbetween said proximal portion of said surgical implement and a distalportion of said surgical implement.
 14. The surgical hand instrument forseparating tissue layers according to claim 12 wherein said vibrationaltranslator further comprises a pivot mount and said actuator isconnected to said pivot mount.
 15. The surgical hand instrument forseparating tissue layers according to claim 3 wherein said tip of saidsurgical implement further comprises a semi-sharp spatula.
 16. Thesurgical hand instrument for separating tissue layers according to claim3 wherein said tip of said surgical implement further comprises a bluntspatula.
 17. The surgical hand instrument for separating tissue layersaccording to claim 3 wherein said surgical implement further comprises around blunted wire.
 18. The surgical hand instrument for separatingtissue layers according to claim 3 wherein said tip of said surgicalimplement further comprises a loop.
 19. A surgical hand instrumenttissue separator comprising: a handle sized as a handheld surgical handinstrument; an actuator mounted in said handle; a surgical implementhaving a generally planar tip, wherein said surgical implement ismechanically linked to said handle and said actuator applies a vibrationto said surgical implement wherein said vibration has a liftingcomponent perpendicular to a plane defined by said generally planar tipof said surgical implement and wherein said lifting component has avibration frequency of 200 Hz to 500 Hz; a control circuit connected tosaid actuator; and a power source connected to said control circuit. 20.The surgical hand instrument tissue separator according to claim 19wherein said tip comprises a blunt spatula.
 21. The surgical handinstrument tissue separator according to claim 19 wherein said liftingcomponent has a vibrating frequency in the range of 200 Hz to 300 Hz.22. The surgical hand instrument tissue separator according to claim 19further comprising a first damping element between said handle and saidactuator and a second damping element arranged to interact with saidsurgical implement and provide a damping effect to said surgicalimplement.